Inside Health

Q & A; Dietary Dilemma

By C. CLAIBORNE RAY

Published: January 26, 2010

Q.Since vitamin D is a fat-soluble vitamin, is the supplement I take with my low-fat breakfast being absorbed? I eat half a grapefruit, shredded wheat with banana, nonfat yogurt and nonfat milk.

A. ''Yes, so long as you continue to include the yogurt and milk,'' said Dr. Sheldon S. Hendler, co-editor of the ''PDR for Nutritional Supplements,'' the standard reference in the field.

Vitamin D binds to certain proteins as well as to fats, Dr. Hendler said by e-mail, and yogurt and milk fill the bill. These are the same proteins that bind to vitamin D in D-fortified nonfat milk, he said. D supplements are well absorbed when accompanied by foods rich in oils, including fatty fish like salmon and tuna and olive oil dressings.

''Typically,'' he said, ''a generous splash of olive oil would be enough to promote good absorption.''

There is wisdom in including healthy fats even in a low-fat diet, he said. ''Although fats typically are thought of negatively (e.g., trans fats), there are some that are truly healthy and that may decrease the risk of cardiovascular and other degenerative diseases,'' he said. ''These include the omega-3 fish oils DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid); the omega-3 plant fats such as alpha-linolenic acid (ALA), found in flaxseed oil; olive oil; and phytosterols and phytostanols, derived from plants, which are known to lower cholesterol levels.''

C. CLAIBORNE RAY

Submit questions to Question, Science Times, The New York Times, 620 Eighth Avenue, New York, N.Y. 10018, or to question@nytimes.com.